Old Manual Focus Lenses on the D7500

Let's start with chipped lenses, such as the Voigtlander 40mm f/2. Mounts and meters just fine. You do have to set the aperture ring on the lens to minimum (f/22), which is Nikon's usual requirement. But in terms of metering and controlling the aperture, it appears that the D7500 handles this and similar chipped lenses just fine in normal shooting modes.

It's when you put an unchipped AI lens—such as my old 58mm f/1.2 NOCT—on the D7500 that you discover that Non-CPU Lens Data isn't available, and there's no AI indexing tab on the camera. Thus, you get F-- flashing in the aperture spot no matter how you set the lens in any of the automated exposure modes, and the shutter release is deactivated.

You can move the Mode dial to M (manual exposure). The Aperture will still be reported as F--, but now you can shoot. The meter won't be of any help to you, you'll need to set exposure manually from some other source (e.g. light meter).

What I noticed with the NOCT is the usual problem with doing manual exposure this way: that the expected result is something off from the actual result. This is a bit due to the way the old AI systems worked. With fast lenses, you often needed to throw in a bit of compensation to align an external meter to the actual result produced. 

But there's a simple enough workaround. Use Live View. 

In Still Live View, press the i button and make sure Exposure Preview is turned to On. Now dial in your exposure visually. This seems to work well, especially once you learn to judge what the LCD is telling you in bright light. In dimmer light, it's easy enough to see where the right exposure probably is. 

Make sure you're in the Still version of Live View. In the Movie version, you have all kinds of odds and ends that will get in your way, and I couldn't find a way to get visual confirmation of exposure. This is another indicator that Nikon is just 100% lost when it comes to video. Many of us use old primes on our video cameras, as autofocus and auto exposure are typically visually annoying in video. But Nikon seems to have crippled the D7500 in this respect. 

Even with a chipped lens, it seems that Nikon has completely messed up something when still shooting in Video Live View. Neither the shutter speed nor aperture set is respected. This appears to be true in both Auto ISO Control (mode M) and not. Video recording, however, works correctly and respects the shutter speed and aperture that you set. 

The problem I have with all this is not so much that Nikon removed a feature, but rather that it is clear that the camera is doing something it shouldn't be, even when using an older lens that should be recognized. I'll have to look much more into this, but this doesn't seem to say a lot in favor of Nikon's QA testing matrix for firmware. 

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